Controlling quantum discord dynamics in cavity QED systems by applying a classical driving field with phase decoherence

We investigate a two=level atom interacting with a quantized cavity field and a classical driving field in the presence of phase decoherence and find that a stationary quantum discord can arise in the interaction of the atom and cavity field as the time turns to infinity. We also find that the stationary quantum discord can be increased by applying a classical driving field. Furthermore, we explore the quantum discord dynamics of two identical non=interacting two-level atoms independently interacting with a quantized cavity field and a classical driving field in the presence of phase decoherence. Results show that the quantum discord between two atoms is more robust than entanglement under phase decoherence and the classical driving field can help to improve the amount of quantum discord of the two atoms.

Classical-driving-assisted coherence dynamics and its conservation

We investigate the quantum coherence and quantum entanglement dynamics of a classical driven single atom coupled to a single-mode cavity. It is shown that the transformation between the atomic coherence and the atom-field entanglement exists, and can be improved by adjusting the classical driving field. The joint evolution of two identical single-body systems is also studied. The results show the quantum coherence transfers among composite subsystems, and the coherence conservation of composite subsystems is obtained. Moreover, the classical driving field can be used to suppress the decay of the coherence and entanglement, owing to considering the leaky cavity. The non-Markovian dynamics of the system is also discussed finally.

Shape gradient and classical gradient of curvatures:driving forces on micro/nano curved surfaces

Recent experiments and molecule dynamics simulations have shown that adhesion droplets on conical surfaces may move spontaneously and directionally. Besides, this spontaneous and directional motion is independent of the hydrophilicity and hydrophobicity of the conical surfaces. Aimed at this important phenomenon, a gen- eral theoretical explanation is provided from the viewpoint of the geometrization of micro/nano mechanics on curved surfaces. In the extrinsic mechanics on micro/nano soft curved surfaces, we disclose that the curvatures and their extrinsic gradients form the driving forces on the curved spaces. This paper focuses on the intrinsic mechanics on micro/nano hard curved surfaces and the experiment on the spontaneous and directional motion. Based on the pair potentials of particles, the interactions between an isolated particle and a micro/nano hard curved surface are studied, and the geometric foundation for the interactions between the particle and the hard curved surface is analyzed. The following results are derived： （a） Whatever the exponents in the pair potentials may be, the potential of the particle/hard curved surface is always of the unified curvature form, i.e., the potential is always a unified function of the mean curvature and the Gaussian curvature of the curved surface. （b） On the basis of the curvature-based potential, the geometrization of the micro/nano mechanics on hard curved surfaces may be realized. （c） Similar to the extrinsic mechanics on micro/nano soft curved surfaces, in the intrinsic mechanics on micro/nano hard curved surfaces, the curvatures and their intrinsic gradi- ents form the driving forces on the curved spaces. In other words, either on soft curved surfaces or hard curved surfaces and either in the extrinsic mechanics or the intrinsic mechanics, the curvatures and their gradients are all essential factors for the driving forces on the curved spaces. （d） The direction of the driving force induced by the hard curved surface is independent of the hydrophilieity and hydrophobicity of the curved surface, explaining the experimental phenomenon of the spontaneous and directional motion.

Generation of W-Type Entangled Coherent States of Three-Cavity Fields by a Driving Classical Field

A scheme is proposed to generate the W-type entangled coherent states of three-cavity field. The scheme is based on the resonant atom-field interaction, thus the interaction time between the atom and the cavity is greatly reduced, which is important in view of decoherence. Furthermore, the scheme does not need accurate adjustment of the interaction time.

Quantum coherence preservation of atom with a classical driving field under non-Markovian environment

The exact dynamics of an open quantum system consisting of one qubit driven by a classical driving field is investigated. Our attention is focused on the influences of single-and two-photon excitations on the dynamics of quantum coherence and quantum entanglement. It is shown that the atomic coherence can be improved or even maintained by the classical driving field, the non-Markovian effect, and the atom-reservoir detuning. The interconversion between the atomic coherence and the atom-reservoir entanglement exists and can be controlled by the appropriate conditions. The conservation of coherence for different partitions is explored, and the dynamics of a system with two-photon excitations is different from the case of single-photon excitation.

Optimum Determination of Partial Transmission Ratios of Mechanical Driven Systems Using a V-belt and a Three-Step Helical Gearbox

This paper introduces a new study on the optimum calculation of partial transmission ratios of a mechanical drive system using a V-belt and a three-step helical gearbox in order to get the minimum size of the system. The chosen objective function was the cross section dimension of the system. In solving the optimization problem, the design equation for pitting resistance of a gear set was investigated and equations on moment equilibrium condition of a mechanic system including a V-belt and three helical gear units and their regular resistance condition were analysed. From the results of the study, effective formulas for determination of the partial ratios of the V-belt and three-step helical gearboxes were introduced. As using explicit models, the partial ratios can be determined accurately and simply.

Optimum Determination of Partial Transmission Ratios of Mechanical Driven Systems Using a V-belt and a Helical Gearbox with Second-Step Double Gear-Sets

This paper presents a study on the optimum determination of partial transmission ratios of a mechanical drive system using a V-belt and a helical gearbox with second-step double gear-sets in order to get the minimum size of the system. The chosen objective function was the cross section dimension of the system. In the optimization problem, the design equation for pitting resistance of a gear set was investigated and equations on moment equilibrium condition of a mechanic system including a V-belt and a helical gearbox with second-step double gear-sets and their regular resistance condition were analysed. Based on the results of the study, effective formulas for calculation of the partial ratios of the V-belt and a helical gearbox with second-step double gear-sets were proposed. By using explicit models, the partial ratios can be determined accurately and simply.

自动驾驶汽车横向控制方法研究综述

为实现精确、稳定的横向控制,提高车辆自主行驶的安全性和保障乘坐舒适性,综述了近年来自动驾驶汽车横向控制方法的最新进展,包括经典控制方法和基于深度学习的方法,讨论了各类方法的性能特点及在应用中的优缺点,并针对自动驾驶汽车横向控制方法的发展趋势进行了展望。

Optimization Transmission Efficiency with Driver Intention for Automotive Continuously Variable Transmission under Slip Mode

This study proposes and experimentally validates an optimal integrated system to control the automotive continuously variable transmission(CVT)by Model Predictive Control(MPC)to achieve its expected transmission efficiency range.The control system framework consists of top and bottom layers.In the top layer,a driving intention recognition system is designed on the basis of fuzzy control strategy to determine the relationship between the driver intention and CVT target ratio at the corresponding time.In the bottom layer,a new slip state dynamic equation is obtained considering slip characteristics and its related constraints,and a clamping force bench is established.Innovatively,a joint controller based on model predictive control(MPC)is designed taking internal combustion engine torque and slip between the metal belt and pulley as optimization dual targets.A cycle is attained by solving the optimization target to achieve optimum engine torque and the input slip in real-time.Moreover,the new controller provides good robustness.Finally,performance is tested by actual CVT vehicles.Results show that compared with traditional control,the proposed control improves vehicle transmission efficiency by approximately 9.12%-9.35%with high accuracy.

Enhancing entanglement generation of two atoms in a cavity with white noise using classical driving fields

We investigate the entanglement dynamics of a quantum system consisting of two two-level atoms in a cavity with classical driving fields in the presence of white noise. The cavity is initially prepared in the vacuum state. Generally, the entanglement of two atoms decreases with the intensity of the thermal fields and the coupling strength of the two-level atoms to the thermal fields. However, we find that the entanglement of the quantum system can be enhanced by adjusting the frequency and the strength of the classical driving fields in the presence of white noise.

曲率的形状梯度和经典梯度:微纳米曲面上的驱动力

近期的实验和分子动力学模拟均表明:圆锥面上粘附液滴能自发地定向运动,且自发定向运动的方向与粘附面的亲水、疏水性质无关.针对这一重要现象,拟从曲面微纳米力学几何化的角度,提供一般性的理论解释.借助于粒子对势,研究了孤立粒子与微纳米硬曲面之间的相互作用,分析了粒子/硬曲面相互作用的几何学基础.可以证实:(a)粒子/硬曲面的作用势均具有统一的曲率化形式,均可以统一地表达成曲面平均曲率和Gauss曲率的函数;(b)基于曲率化的作用势,能够实现曲面微纳米力学的几何化;(c)曲率与曲率的内蕴梯度构成卷曲空间上的驱动力;(d)驱动力方向与曲面的亲水、疏水性质无关,解释了自发定向运动实验.

列车驾驶模拟器经典洗出算法的参数优化

洗出算法参数的选择对模拟器逼真度有直接的影响。针对目前应用于列车驾驶模拟器经典洗出算法参数选择的不足,根据经典洗出算法原理推导出整体传递函数关系式作为目标函数,以定量表述平台运动空间、响应能力和人体感觉阈值对模拟器逼真度的影响作为约束条件,选择简洁、灵活的极点配置滤波器方程,利用遗传算法进行优化,寻找出最适合模拟器配置的算法参数。运用MATLAB软件,对优化前后的平台运动和人体运动感觉进行比较,结果显示优化后经典洗出算法参数明显提高了模拟器的逼真度。

莱州湾南岸咸水入侵区土地利用/覆被变化驱动机理研究

借助于典型自相关模型分析,将众多变量归纳为少数几个综合变量,并分别就这些综合变量进行系统阐述。影响研究区土地利用变化的社会经济因素可以归纳为:人口增长、产业结构调整、工业发展与城镇化等综合指标,并分别对各不同影响因素进行阐述。在自然因素方面,咸水入侵与土地利用结构特征及其变化方向具有相关性,它是可以综合反映自然驱动因素的代表性因子。

利用非最大纠缠态实现未知原子态的受控隐形传态(英文)

提出一个利用三粒子非最大纠缠态传送未知原子态的腔QED方案。这个方案的主要优点是隐形传态和纯化过程能够同时进行,而且与腔衰减和热场无关,不用预先将非最大纠缠态量子通道纯化为最大纠缠态。另外,联合Bell态测量可以转化为单原子测量。

基于ABAQUS的微型车驱动桥壳有限元分析

运用UG三维设计软件建立某微型车整体式驱动桥壳数模,基于HyperMesh、ABAQUS软件平台,建立该车驱动桥壳的FEA模型并进行有限元分析;在4种典型工况下分析获得的应力云图和位移图表明该桥壳的强度与刚度均能满足设计要求,计算效率高,并能在一定程度上缩短桥壳的开发周期,降低研发费用,可为驱动桥壳前期设计阶段精确高效地预测桥壳结构强度、刚度提供指导.

AB类功率放大器驱动电路的研究与设计

功率放大器是无线系统的重要组成部分,驱动电路是任何一类功放都必不可少的。各类功放的设计已有大量的文献发表,但只有较少的专利和文献涉及驱动电路的设计。AB类功率放大器是目前应用比较多的一种,因此AB类功放驱动电路的研究具有重要意义。针对MOS管的BSIM3模型,提出和分析了AB类经典功放的多种驱动电路方案,最后用HSpice对每个所设计的驱动电路进行了精确的仿真,验证了其可行性及正确性。

基于经典偏最小二乘模型的CO_2排放量宏观驱动因素分析

CO2排放量可认为是社会、经济、自然等多种宏观驱动因素共同作用的结果。基于此,本文通过采集1952～2006年期间我国CO2排放量相关的36个指标,用经典偏最小二乘模型(PLS)对它们的重要性进行辨识。结果表明:重要的宏观驱动因素是总人口量、城市人口率、GDP及人类生产生活等活动强度较大的指标(如财政收入与投资、运输与邮电、医疗卫生及文化教育),不重要的宏观驱动因素则为人类活动强度较弱的指标(如农村人口、艺术表演水平和金融外贸活动)或自然环境条件等。据此,提出了几点有利于低碳将来的对策建议。

经典场驱动对量子系统生存概率的影响

考虑一个受经典场驱动的二能级系统与零温玻色子库相互作用,研究经典场驱动对量子Zeno效应和量子反Zeno效应中量子系统存活概率的影响.结果表明,经典场驱动可以降低量子系统的有效衰减率,即提高量子系统的存活概率.此外,环境的欧姆性对于提高量子系统的存活概率也起着重要作用,设置适当的环境欧姆参数可降低量子系统的有效衰减率.再者,随着二能级系统与经典场之间失谐量的增加,量子系统的存活概率降低,而通过增加经典场驱动的强度或选择合适的环境欧姆参数,可以抑制失谐带来的负面影响.

经典激光场驱动下的两量子比特纠缠动力学(英文)

利用超算符的方法研究了在经典激光场驱动下,分别囚禁在两个独立腔中的两个二能级原子的纠缠动力学。结果表明:两原子纠缠与腔场相干态的初始值无关,并且在腔场耗散比较小的时候,经典光驱动场会加速两原子的纠缠突然死亡,在腔场耗散比较大的时候,经典驱动场可以保护原子纠缠免于突然死亡。这说明即便在"坏"腔中,也可以通过加经典驱动场来避免原子纠缠突然死亡。

普通V带传动的优化设计

在普通V带传动设计中 ,传统设计方法存在查找手册工作量大、效率低的不足 ,且所得设计方案未必是最佳设计方案 .提出了以小带轮直径d、两带轮中心距a为设计变量 ,以两带轮体积和最小为设计目标 ,对小带轮直径d、小带轮包角α、中心距a、带线速度v、带根树z等建立约束条件的优化设计数学模型进行优化设计的方法 .通过设计实例说明 ,用该优化设计方法进行普通V带传动设计 ,在满足传动能力要求的前提下 ,可减轻传统设计中查找手册的工作量 ,提高设计效率 ,且能设计出具有最佳尺寸的V带传动结构 .